Light‐Operated Transient Unilateral Adhesive Hydrogel for Comprehensive Prevention of Postoperative Adhesions

Dislocation of anti-adhesion materials, non-specific tissue adhesion, and the induction of secondary fibrinolysis disorders are the main challenges faced by postoperative anti-adhesion materials. Herein, a self-leveling transient unilateral adhesive hydrogel is custom-designed to conquer these challenges with a theoretically calculated and dual-step tailored gellan gum (GG) as the sole agent. First, the maximum gelation temperature of GG is lowered from 42-25 °C through controlled perturbation of intra- and inter-molecular hydrogen bonds, which is achieved by employing the methacrylic anhydride as a "hydrogen bond's perturbator" to form methacrylate GG (MeGG). Second, the "self-leveling" injectability and wound shape adaptably are endowed by the formation of borate-diol complexed MeGG (BMeGG). Finally, the transient unilateral tissue-adhesive hydrogel (BMeGG-H) barrier is prepared through photo-controlled cross-linking of reactive alkenyl groups. This degradable hydrogel demonstrates favorable rheological properties, light-controlled unilateral adhesion properties, biocompatibility, anti-fibrin adhesion, and anti-cell adhesion properties in vitro. Comprehensive regulation of the fibrinolysis balance toward non-adhesion is conformed in a rat model after intra-abdominal surgery via anti-autoinflammatory response, intestinal wall integrity repair, and Tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) balance adjustment. Notably, the 14^th day anti-adhesion effective rate is 100%, indicating its significant potential in clinical applications for postoperative anti-adhesion.